Rapid dye-bleach photographic process and element comprising dye-developers



United States Patent Office 3,498,787 Patented Mar. 3, 1970 3,498,787 RAPID DYE-BLEACH PHOTOGRAPHIC PROC- ESS AND ELEMENT COMPRISING DYE- DEVELOPERS Ransford B. Wilson, Carl J. Williams, Jr., and Robert D. Nicholas, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N .Y., a corporation of New Jersey No Drawing. Filed Aug. 20, 1965, Ser. No. 481,406 Int. Cl. G03c 7/02, 7/16, 7/28 US. Cl. 96-53 21 Claims ABSTRACT OF THE DISCLOSURE Silver-dye-bleach photographic elements can be prepared which incorporate at least one photosensitive layer including silver halide and having in association with said silver halide, either in the photosensitive layer or a contiguous hydrophilic colloid layer, either a non-diffusible, bleachable dye and a developing agent free from any dye moiety or a non-diffusible dye developer. These silver halide elements, after a suitable exposure, can be processed to develop silver images by immersion in an alkaline activator solution.

This invention relates to photography, and more particularly to silver-dye-bleach photographic materials and processes.

The silver-dye-bleach process employs a photographic material comprising at least one photosensitive silver halide emulsion layer which is associated with a preformed bleachable dye. A typical multicolor silver-dye-bleach element is composed of three silver halide layers respectively sensitized to red, green, and blue radiation, and having in association therewith, respectively, a bleachable cyan, magenta and yellow dye. The processing of such an element for obtaining a positive multicolored photographic reproduction generally includes exposing said element to a light pattern, developing it to a negative silver image in a black-and-white silver halide developer solution, treating it in a dye-bleach bath which oxidizes the silver image to a silver salt and concurrently decolorizes the associated pattern of dye, and, finally removing the residual silver salt by fixing and washing. A dye image is left which is photographically the inverse of the initial silver image.

Certain deficiencies are inherent both in the composition of conventional multilayer silver-dye-bleach materials and in the methods heretofore used for processing them. By virtue of being composed of various superimposed coating layers, conventional silver-dye-bleach elements require a relatively long processing time for the adequate development of all of the exposed silver halide in each of the light-sensitive layers. Particularly disadvantageous is the frequently observed incomplete reduction of the exposed silver halide in the emulsion layer closest to the support which manifests itself in a poor reproducibility of the contrast of the color to which that layer is sensitive. Relatively long development times are required and inadequate reduction of exposed silver halide is caused by the fact that in these processes the developing agent has to migrate out of the conventional developer solution and into each of the photographic emulsion layers. The control of uniform and equal development of the exposed silver halide in the various emulsion layers is inhibited due to the developer exhaustion which takes place in the outermost layers of the material.

Prolonged development times which may be resorted to as a compensation for such a developer exhaustion for the adequate reduction of the exposed silver halide in the lower emulsion layers usually results in overdeveloping the exposed silver halide in the upper emulsion layers. On

the other hand, shortened development times which may suffice to effectively reduce the exposed silver halide in the upper emulsion layers usually result in an incomplete reduction of the exposed silver halide in the lower emulsion layers. Thus, highly accurate rendition of density and contrast of the intermediate negative black-and-white images recorded in each of the plurality of light-sensitive layers of a multicolor photographic element is not possible when the element is developed conventionally in a blackand-white developing solution. This problem is particularly serious in silver-dye bleach processes because adequate destruction of dye takes place only in situ with adequately reduced silver halide.

Attempts have been made to shorten the processing times required for the development of conventional silverdye-bleach materials by modifying the composition of the developing solution or by developing at elevated temperatures. Such attempts have not been very successful and have resulted in certain disadvantages. Thus, modified developing compositions, which give some increase in speed, have not been stable so that fresh developer must be pre pared just before processing. Using developers at elevated temperatures causes undesirable fog even with short processing times.

It therefore appears highly desirable to provide silver dye-bleach materials and processes whereby uniform silver images are obtained with rapid processing.

One object of this invention is to provide novel photographic silver-dye-bleach materials which are developable within shorter periods of time than prior art silver-dyebleach materials.

Another object of this invention is to provide novel photographic silver-dye-bleach materials, which upon being developed, yield more complete and uniform silver images in each and all of the exposed photosensitive layers.

A further object of this invention is to provide novel photographic silver-dye-bleach .processes which yield improved dye images.

Another object of this invention is to provide novel photographic silver-dye-bleach processes which feature development with simple alkaline activator solutions.

Still another object of this invention is to provide novel methods of processing silver-dye-bleach elements.

Other objects will be apparent from this disclosure and the appended claims.

In accordance with one embodiment of this invention, silver-dye-bleach elements are provided comprising a support having coated thereon at least one silver halide emulsion layer, which layer has in association therewith a nondiifusible bleachable dye and a developing agent free from any dye moiety.

In another embodiment of this invention, silver-dyebleach elements suitable for providing multicolored images are provided comprising a support having coated thereon separate overlying light-sensitive silver halide emulsion layers, each of said layers having in association therewith a non-diifusible bleachable dye and a developing agent free from any dye moiety. In preferred arrangements, at least three separate light-sensitvie silver halide emulsion layers are provided which are respectively sensitized to red, green, and blue radiation and which have in association therewith, respectively, non-diffusible bleachable cyan, magenta and yellow dyes, and at least two separate non-light-sensitive hydrophilic colloid layers containing developing agent free from any dye moiety, said layers being arranged so that each of said light-sensitive layers is contiguous to at least one of said hydrophilic colloid layers. Especially good results are obtained when the dye-bleach element has a dye-bleach catalyst incorporated therein, preferably in a light-sensitive layer thereof. The presence of catalyst in association with a light-sensitive layer in elements in accordance with the invention functions to further decrease processing time.

'In a further embodiment of this invention, a process is provided for developing the silver halide to a silver image in silver-dye-bleach elements having an alkali-activatable (at a pH over about 9.0) developing agent in association with a silver halide emulsion having a pH lower than about 7.0, which features raising the pH of the emulsion to at least 9.0, and preferably over 10.5, such as up to about 12.0. Especially good results are obtained at a pH of about 11.5. Advantageously, the'pI-l of the emulsion is raised by contacting it with an alkaline solution.

We have found that the photographic elements and processes of this invention allow rapid development and provide improved color images. Elements of the invention have less processing mottle than prior alt dye-bleach materials.

In another embodiment of this invention, a novel process for obtaining positive dye images in an exposed photographic elementcomprising a support having coated thereon light-sensitive silver halide dispersed in a hydrophilic colloid binder, said layer having incorporated therein or in a contiguous hydrophilic underlayer, a non-diffusible dye developer, said dye developer containing within each molecular both a bleachable dye moiety and a developing agent moiety by contacting said element with an alkaline solution to develop a negative silver image therein at a pH below that which will cause diffusion of said dye developer; and, bleaching said dye developer only in the areas of said silver image. The process of this embodiment of the invention is useful in producing multicolored records, for example by using photographic elements having separate layers sensitive to blue, green and red radiation, each of said layers containing, respectively, yellow, magenta and cyan dye developers. If desired, a cross-oxidizing auxiliary developer may be present in or contiguous to the light-sensitive layer. In accordance with this process, development is effected under alkaline conditions, but at a pH lower than that which will cause diffusion of the bleachable dye. The most useful pH ranges are from about 9.5 to about 12.0 or 12.5. At higher pH levels, such as 13 to 14, diffusion of the dye developer results in the loss of satisfactory color rendition. Especially rapid development may be achieved by adding a black-and-white developer to the alkaline solu tion. Preferably, bleaching of the dye is conducted in the presence of a dye-bleach catalyst, which may be incorporated in the light-sensitive layer, a layer contiguous thereto, or in the processing solutions. Thereafter, the metallic silver may be removed in any convenient manner leaving the dye image.

We have found that the foregoing process produces excellent dye images of exceptionally high dye density. Particularly good image sharpness is realized with this process of the invention. Moreover, the photographic elements used in the process of the invention are developable to a silver image with a simple alkaline solution. Manufacture of elements used in the process requires the addition of but one dispersion containing the dye-developers employed herein.

The dye developers employed herein are, under the processing conditions used, non-diifusible in the sense that they do not migrate through or out of the entire photographic element. They may be slightly mobile under the processing conditions used so that the dye developer will move into an overlying, contiguous silver halide emulsion. This property of the dye-developers permits use thereof, therefore, either in the emulsion layer or in a layer below the emulsion layer and contiguous thereto. Hence, as used herein and in the appended claims, the term non-diffusible refers to the fact that the dye developers will not bleed out of the photographic element or diffuse into non-contiguous layers of the element. Gelatin interlayers may be employed in multilayer coatings to assist in preventing diffusion of dye-developer into certain layers.

Developing agents which may be incorporated in silyer-dye-bleach elements in accordance with the invention include all of those which are compatible within the predominantly aqueous medium of photographic silver halide emulsions and which have no adverse effects on such emulsions. As used herein and in the appended claims, the term developing agents includes developing agent precursors which release developing agent on treatment at high pH, 'e.g., with alkali.

Any conventional developing agents may be used including, for example: p-phenylenediamines, p-aminophenols, hydroquinones, aminopyrazoles, aminopyrazolines, pyrazolidones, o-phenylenediamines, o-aminophenols, p-aminophenols, o-diaminophenols, p-diaminophenols, 3-pyrazolidones, 4-aminopyrazolones, 3-aminopyrazolines.

Other conventional developing agents may also be used including, for example, ascorbic acid, cathechols, etc. Still other useful developers are disclosed in the following patent literature: U.S. Patents 2,592,368; 2,596,756; 2,751,295; 2,856,283; 2,751,297; 3,142,564; 2,614,927; French Patent 1,359,923 based on U.S. Ser. No. 183,354; British Patents 803,783; 813,253; and 655,273.

Also useful in this invention are developing agents, sometimes referred to as developer-precursors, which release developer upon treatment at high pH, for example with alkaline solutions.

Developing agent precursors useful in the photographic elements of the invention include the amide compounds disclosed in U.S. Ser. No. 183,354, filed Mar. 29, 1962, now abandoned and continuation-in-part of U.S. Ser. No. 373,050, filed June 5, 1964, and now Patent No. 3,291,609. Typical useful developing agent precursors disclosed therein which are useful in this invention have the general formula:

wherein R represents alkyl or halogenoalkyl, R represents a hydrogen atom or an alkyl group, and R represents a hydrogen atom, an alkyl group, a halogen atom, an alkoxyl group, an acylamido group or an acyloxy group. Specific useful developing agent precursors include o-(N- trifluoracetyl)aminophenol; p (N trifiuoracetyDaminophenol and 2,4-(N,N-trifluoracetyl) diaminophenol.

It has been found that the development rate of such developing agent precursors can be improved by adding an auxiliary developing agent either to the silver halide emulsion layer, or a hydrophilic layer contiguous thereto. Typical auxiliary developing agents include those described in the copending application Ser. No. 134,014, filed Aug. 5, 1961, now abandoned, of RH. Stewart, G. E. Fallesen and J. W. Reeves, Jr.

Typical auxiliary developing agents described in this application include 3-pyrazolidone, compounds containing an alkyl (e.g., methyl, ethyl, etc.) or aryl substitutent (e.g., phenyl p-tolyl, etc.). In addition, such pyrazolidone developing agents can contain an acyl or acyloxy substituent which can be hydrolyzed from the 3-pyrazolidone compound by treatment with the above activator solutions to produce the desired auxiliary developing compound. Typical auxiliary developing agents include, for example, l-phenyl-3-pyrazolidone, 1-p-tolyl-3-pyrazolidone, l-phenyl-5-methyl-3-pyrazolidone, l-acetamidophenyl-3-pyrazolidone, 3-acetoxy-1-phenyl-3-pyrazolidone (enol ester), 2-(pyridinium acetyl)-l-phenyl-3-pyrazolidone chloride, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-

phenyl-4-methyl-3 -pyrazolidone, l-phenyl 2 benzoyl-3- pyrazolidone, 1-phenyl-2-lauroyl-3-pyrazolidone, l-phenyl-2-chloroacetyl-3-pyrazolidone, etc.

The concentration of auxiliary developing agents can be varied, and of course, no auxiliary developing agent need be employed unless so desired. Useful concentrations of auxiliary developing agents vary from about 0.01 mole to 2.0 moles per mole of the precursor. Depending upon the particular auxiliary developing agent employed, larger or smaller quantities can be used.

The concentration of the developing agent used in the invention will vary, depending upon the particular chemical compound involved and the location of the compound within the photographic element. If the developing agent is incorporated within the silver halide emulsion layers undergoing development, it may be desirable to use a somewhat difierent concentration than would be used if the developer were incorporated in a layer contiguous to the photographic silver halide emulsion. A preferred concentration of developer for incorporation in the emulsion is from about 0.1 to 4.0 moles per mole of silver halide. A particularly useful range is from about 0.25 to 2.0 moles per mole of silver halide, with especially useful results being obtained within the range of about 0.4 to 1.0 moles per mole of silver halide. For incorporation in layers contiguous to the silver halide emulsion layers, somewhat larger concentrations of developer compound can be tolerated without adverse effects. The relative concentrations of the developing agents associated with the various photographic materials of the invention can be varied, for instance, in such a way that the concentrations of developing agents associated with the lower of the photosensitive layers is progressively higher than in the upper photosensitive layers.

The developing agents are advantageously added to the photographic materials of the invention in any convenient manner, depending on the chemical composition and compatibility at the desired concentrations with the predominantly aqueous medium of the photographic material. The developing agents can be diffusible or ballasted so to remain essentially stationary in the photographic element. Also useful are developing agents which may be introduced into the photographic element according to coupler solvent dispersion techniques. Certain developing agents can be added from an aqueous solution, others, e.g., by the Fischer method, such as that as applied to dye-forming couplers described in U.S. Patent 2,186,849, and as applied to ultraviolet absorbers as described in U.S. Patents 2,685,512; 2,719,086; 2,739,888; and 2,784,087.

Nondiifusing developing agents can be incorporated in the emulsion layers or in layers adjacent thereto by solvent dispersion techniques such as are described for oil-soluble couplers in U.S. Patent 2,304,939, U.S. Patent 2,322,027, high-boiling organic solvents and by methods described in U.S. Patent 2,801,171 and U.S. Patent 2,949,- 360, in which low-boiling or water-soluble organic solvents are used with or in place of the high-boiling solvent.

The distribution of the developing agents within the photographic element can be varied to include the presence of developing agents either in all or only one of the photosensitive layers or in several or only one separate non-light-sensitive layer adjacent to the silver halide emulsion layer.

Combinations of various kinds of developing agents can be used. The embodiments of our invention also make allowance for the additional presence in our photographic material of development accelerators as are, for example, disclosed in the Belgian Patent 621,608, based on U.S. Ser. No. 134,014, filed Aug. 25, 1961, of development promoter precursors, for example, the esters disclosed in U.S. Patent 3,041,170. The developing agents in our photographic materials can be tanning developers, for example, those disclosed in U.S. Patents 2,592,368,

6 2,596,756; 2,751,295; 2,856,283. The use of tanning developers in our system is considered to be advantageous based on the following considerations: development of the silver halide takes place in those areas of our photographic element, which upon completion of the processing cycles, are void of any dye and therefore transparent to white light. When development is effected by the use of a tanning developer, the gelatin associated with the silver halide being reduced in these areas is insolubilized and contracts. This contraction provides for a somewhat thinner gelatin stratum and, consequently, a more transparent element which results in a reproduction having colors of improved brilliance.

The choice of kind, activity, distribution, concentration, and method of dispersing developing agents can, of course, be determined depending on the particular silverdye-bleach materials used, on the composition of the activator available or preferred, and on specific visual characteristics which the final reproduction is designed to exhibit.

Dyes useful in the developer-containing elements of our invention are those commonly employed in silverdye-bleach materials and include the dye disclosed, for instance, in Gaspar, U.S. 2,055,407 and U.S. 2,564,238 and in British Patents 939,009; 940,286, and 607,792; azoxy dyes disclosed in Swiss Patent No. 386,247, published Apr. 15, 1965.

The bleachable dye-developers employed herein are molecules which contain both a bleachable dye moiety and a moiety which develops exposed silver halide to metallic silver, the developing action taking place only under alkoline conditions at a pH of over about 9.0 and at a pH less than that which will cause unwanted diffusion of the dye developer in the hydrophilic colloid in which such agents are incorporated. These dye developers are used in similar concentrations, and dispersed in emulsions in a similar manner, to the dye-free developing agents described obove. Dye developers useful herein may be represented by the following formula:

wherein D represents the bleachable dye moiety, D the developing moiety and X a suitable linking group. Thus, D can be any dye capable of being reduced by suitable bleaching agents in the presence of metallic silver and, as a result of this action, is decolorized; e.g., azo dyes, oxazine dyes, and certain anthraquinone dyes, phthalocyanine dyes, triphenylmethane dyes, fortmazans, and salts of formazans; D is a group containing an aryl nucleus substituted by at least two substituents selected from hydroxyl, amino, and substituted amino groups, so that the resulting compound is capable of reducing exposed silver halide to metallic silver; and, X is a linking group such as: -CO; -CR wherein R can be hydrogen, alkyl, or aryl; SO CR wherein R is a di-bonded hydrocarbon residue; e.g., alkylene or aryl;

-COR'CO, e.g., a diacyl residue 'of a dibasic organic acid or of an acid anhydride;

SO R'NH-; or, X may be a di-bonded alicyclic or heterocyclic residue; e.g., a cyclohexyl ring or an striazinyl ring. The s-triazinyl radical which constitutes the linking group may be further substituted by a second dye unit or developer unit whereby the developing potential or the color properties of the dye developer may be adjusted to meet a particular need. Bleachable dye developers employing the group CO-alkylene as the linking group may be prepared by reacting a dye containing at least one primary or secondary reactive amino group with a derivative of a compound of the formula:

where D is a dye unit. Examples of dyes which may be obtained as a product of the above reaction are:

reactive amino group, to obtain dye developers of the formula:

NaOaS Compounds having the formula:

0 lTTHCHzCHzNHz and the formula:

O NHz are examples of bleachable dye developers employing a -CH CONH group as the linking bond. Dye developers of the type described above can be prepared by uniting a dye of a desired predetermined color with a group possessing a silver halide developing function to obtain a dye developer having substantially the same color as the chosen dye and substantially the same developing power as the developer. Use of such techniques thus permits one to obtain dye developers of predetermined color characteristics and thus greatly broadens the field of choice of dye developers.

The following dye developer is an example that can advantageously be used in a silver-dye-bleach element according to my invention:

NH C-CHz-NH 0 H 0 H30 0 H I I!) N: --N=N S O3Na l S OaNa S O 3N8,

suitable compounds which form developer moieties in combination with out bleachable dyes are:

Hydroquinones- Hydroquinones substituted with groups such as amino,

alkylamino, alkyl, hydroxyl, alkoxy, halogen Catechols Pyrazolidones, for instance those disclosed in US. Patent No. 2,751,297, assigned to Kodak Ltd.

Open chain, carboxylic and heterocyclic developing agent groups can be used, e.g., residues of ascorbic acid, aromatic developing agents, such as substituted benzenes and variously substituted pyrazolidones.

As employed herein and in the appended claims, the term non-dififusible refers to bleachable dye or to bleachable dye developers which do not bleed out of the photographic element, or into layers other than contiguous layers at the pH coated, or at the elevated pH used during processing.

It will be noted that this invention relates to photographic elements and processes, including both development and bleaching of the elements employed herein.

Silver images can be obtained in exposed silver-dyebleach elements by raising the pH thereof to over about 9.0 and preferably over 10.5. Advantageously, the pH is raised by treatment with an alkaline material, such as an activator solution. Typically activator baths comprise, for example, an aqueous solution of an alkaline material, such as sodium carbonate, sodium hydroxide, potassium carbonate, potassium hydroxide, mixtures of sodium hydroxide and sodium sulfite, etc. A bath of the latter type is quite suitable for developing an exposed silver-dyebleach film strip in about 30 seconds when the activator bath is at about 68 F. Modifications can easily be made in the activator baths without departing from the spirit and scope of the invention.

For example, an aqueous solution comprising about 4% of sodium carbonate and 5% of sodium sulfite produces development in about seconds at 68 F. Another aqueous activator solution comprising 2% sodium hydroxide and 5% sodium sulfite produces useful photographic images in a few seconds when heated to 130 F. Particularly useful activator solutions have a pH of at least about 9.0 and preferably of at least about 10.5.

The activator solutions can be applied according to the present invention in any number of known ways, such as by dipping, spraying, or other suitable surface applications. If desired, a thickener can be added to the activator solution to increase the viscosity of the composition and make it more adaptable for continuous processing. Viscous compositions can then be removed by squeegeeing or water spraying.

As noted above, especially good results are obtained in accordance with this invention by incorporating in dyebleach materials a dye-bleach catalyst along with developing agent. The dyeblaech catalyst may be incorporated in the same layer as the developing agent, or in a separate layer. Good results can be obtained by incorporating the dye-bleach catalyst in a layer contiguous to the light-sensitive layer. Preferably, the catalyst is incorporated in one or all of the silver halide emulsion layers. The presence of dye-bleach catalyst serves to further reduce processing times of the elements of the invention, and to provide superior color images. Any elfective concentration of catalyst may be employed. Good results are obtained with from 5.0 to 80.0 grams of catalyst per mole of silver, with especially good results at 10.0 to 40.0 grams of catalyst per mole silver. Any compound useful for catalyzing dye destruction in the dye-bleach process may be employed.

Phenazine and quinoxaline compounds are especially useful catalysts. Some particularly useful catalysts are listed below:

Phenazine-- 2-hydroxy-3-aminophenazine Z-anthraquin-one sulfonic acid (Na salt) 2-methyl-3-(p-nitrophenyl) quinoxaline Z-methyl pyrazine Z-carbamyl pyrazine 2,3,5,6-tetramethyl pyrazine Quinoxaline- 2-methy1 quinoxaline 6-chloro quinoxaline 6-nitro quinoxaline 6-methyl quinoxaline 6-methoxy quinoxaline 6,7-dimethyl quinoxaline 2,3-bis(2-methyl-6-pyridyl)-6,7-dimethyl quinoxaline 6,7-dimethyl-2,3-diphenyl quinoxaline 6,7-dimethyl-2,3-bis (2-pyridyl) quinoxaline 2,3-diphenyl-6-nitro quinoxaline 2,3,6,7-tetramethyl quinoxaline 2,3-dimethyl quinoxaline 2,3-diphenyl quinoxaline 4-hydroxypteridine 6,7-dimethyl-4-hydroxy-2-mercaptopteridine 2,3 (1,8-naphthyl) quinoxaline 2-carbethoxy-3-rnethoxy quinoxaline (A) A multicolor photographic element is prepared having the following dried layers on a transparent photographic film support (all quantities given are in mg./ft.

Layer A Gelatin Layer B- Blue-sensitive silver bromoiodide emulsion silver 81 Bleachable yellow dye 70 Mordant 200 6,7 dimethyl 2,3 dipyridylquinoxaline (catalyst) 10 Gelatin 242 Layer C- Di-n-octyl benzoquinone (catalyst scavenger) 20 Norbornanehydroquinone (developer) 100 '1-phenyl-3-pyrazolidone (developer) 30 Gelatin 200 Layer D- Green-sensitive silver bromoiodide emulsion silver Bleachable magenta dye 62 Mordant 152 6,7 dimethyl 2,3 dipyridylquinoxaline (catalyst) 20 Methyl arabonate (dye density increasing agent) 200 Gelatin 226 Layer E-Identical with Layer C Layer F Red-sensitive silver bromoiodide emulsion silver 250' Bleachable cyan dye 59' Mordant 6,7 dimethyl 2,3 dipyridylquinoxaline (catalyst) 40 Methyl arabonate (dye density increasing agent) 240 Gelatin 311 Support In this element, the mordant is poly-a-methyl allyl-N- guanidyl ketimine glycollate, described in U.S. Patent 2,882,156. The bleachable yellow dye is Solantine Yellow RL having the formula:

1 1 The bleachable magenta dye is Solantine link 4BL having the formula:

N11 O=O S OaNa 2 The bleachable cyan dye is Diphenyl Fast Blue-Green BL 15 having the formula:

C2135 OH SOaNa S OaNa The above element was exposed through an intensityscale test object for A sec. in an Eastman 1B sensitometer and processed in the following sequence of baths:

Seconds Anti-foggant bath Activator bath 25 Activator Blix bath 25 Water wash 10 The baths used for the above processing consisted of the following ingredients:

Antifoggant bath:

Excellent results were obtained using a total processing time of 65 seconds. The processed material was free from mottle.

(B) A film material as described in Part A, but which does not contain the norbornanehydroquinone and l-phenyl-3-pyrazolidone developing agents, is processed according to the procedure described in Part A, except that the black-and-white developing step is performed in developer DK50 for 3 minutes (this time being the minimum to obtain satisfactory development). A total of processing time of about 3 minutes, 40 seconds is required. In addition, processing mottle appears in the processed element.

It should be noted that the black-and-white development time of prior art dye-bleach materials can be re- 12 v duced to under about one minute with special developers, such as:

Water ml 800 Ascorbic acid gn1 50 4-phenyl-3-pyrazolidone gm l0 Z-aminoethanol ml 100 S-methylbenzotriazole gm 0.5 Potassium bromide gm 5.0 sodium hydroxide solution to adjust pH to 10.5

10 Water to total of liter 1.0

However, such developers are unstable and fresh solutions must be made up just before they are to be used. The activation solutions used in this invention are stable over long periods of time, and the invention provides I S 0 :NB

faster processing times than has been obtained even with special, unstable developers for prior art elements.

EXAMPLE 2 (A) A silver-dye-bleach element is prepared similar to that described in Part A of Example 1, except that the norbornanehydroquinone in Layers C and E is replaced with 120 mg./ft. of 4-methyl phenyl hydroquinone. The

material is processed as in Part A of Example 1, with similar results.

(B) A sample, as described in Part B of Example 1, is processed as described in Part B of Example 1. The results obtained are identical with those described in Example 1.

EXAMPLE 3 The procedure of Example 1, Part A is repeated except that the activator bath (see Part A, Example 1) contains, in addition, 1.0 gm. of 1-phenyl-3-pyrazolidone.

The results obtained are similar to those obtained in Example 1, Part A.

EXAMPLE 4 Two silver-dye-bleach elements, as described in Parts A and B of Example 1, are prepared. Each element is exposed according to the procedures in Example 1, but through a red filter. The element containing developing agents is processed for 30 seconds in the activator solution of Part A of Example 1. The element not containing developing agents is processed for 3 minutes in the developing solution of Part B of Example 1. Each element is then fixed, washed, and dried. Sensitometric evaluation of the black-and-white images in layers F of each sample show a higher maximum density and contrast in the element containing the developing agents and having been processed in the activator solution (i.e., the solution of Part A of Example 1). This example demonstrates that a more complete reduction of the exposed silver halide in the lowest layer of a multilayer silver-dye-bleach material can be effected according to my invention.

EXAMPLE 5 Two silver-dye-bleach elements, as described in Example 1, were exposed through a red filter and processed. A black-and-white developing time of 30 seconds was employed for each element. The developer described in 13 column 11, lines 74-75, and column 12, lines 1-29 was used for the element of Part B. The cyan dye images obtained were sensitometrically evaluated. It was found that the image in the material containing the developing agents had higher contrast and lower minimum dye density.

EXAMPLE 6 Two silver-dye-bleach elements, as described in Parts A and B of Example 1, were prepared. Each element was exposed according to the procedures in Example 1. The element containing developing agents was processed for 30 seconds at atemperature of 125 F. in the activator solution of Part A of Example '1. Separate samples of the element not containing developing agents were processed for 1, 5, l0, and 15 minutes at a temperature of 125 F.-in the developing solution described in column 11, lines 7475, and column 12, lines 1-29. Each element was then fixed, Washed and dried. The element processed with the activator solution gave an excellent color reproduction. The samples processed with the developing solution showed fog which ranged from a low level at the 1 minute development time to complete blackness at the and minute development time. No acceptable image was obtained even at the lowest fog level.

EXAMPLE 7 Results similar to those obtained in Example 1, Part A are obtained when the developer employed is a p-phenylenediamine, a hydroquinone, an aminopyrazole or ascorbic acid and the catalyst is a phenazine, Z-methyl pyrazine, 6-nitroquinoxaline or 2,3-diphenylquinoxaline.

We believe that this invention demonstrates the advantages derived from incorporating developing agents in photographic azo dye-bleach materials which, when processed in suitably selected processing solutions, provide a novel dye-bleach system capable of rendering excellent color reproductions at reduced processing times.

Photographic processes employing dye-developers in accordance with the invention are demonstrated in the following examples.

EXAMPLE 8 A photographic silver-dye-bleach material was prepared by coating on a cellulose acetate film base in sequence the following layers:

Dispersed by means of N,N'-diethyl lauramide In gelatin MAGENTA DYE DEVELOPER on on I CHZ-CHPQN=NA H (INDIE-CH3 2- {p- ,3- (hydroquinonyl ethyl] phenylazo}-4- ethoxy-l-naphthol Layer 3Green-sensitized silver bromoiodide emulsion coated to give a dry coverage of 108 mg./ft. of silver and 60 mg./ ft. of gelatin.

14 Layer 4-Gelatin of a dry coverage of 264 mg./ft.

The above film material was exposed and processed as follows:

(1) Develop for 1.5 minutes in a developer of the following composition:

(2) Wash for 30 seconds. (3) Fix for 1 minute in a solution of the following composition:

Water n ml 500 Sodium thiosulfate g 240.0 Sodium sulfite, dessic g 15.0 28% Acetic acid ml 48.0 Boric acid crystals g 7.5 Potassium alum g 15.0 Water to make liter 1.0

(4) Wash for 30 seconds. (5) Dye bleached for 1 minute in a solution of the following composition:

Water ml 750 Thiourea ml 125 Concentrated hydrochloric acid ml 2-hydroxy-3-aminophenazine g 0.6 Water to make liter 1 (6) Wash for 30 seconds.

(7) Silver bleach 1 minute.

(8) Wash 30 seconds.

(9) Fix in solution (see step No. 3).

(10) Final wash 3 minutes.

After processing, the above sample contained a direct positive magenta dye image.

EXAMPLE 9 A film material was prepared and processed as described in Example 8 except that development was accomplished in 2.5 seconds at 75 F. in the following developer solution:

Water ml 800 Ascorbic acid gr 10 Arninoethanol ml 25 1-phenyl-4-methyl-3-pyrazolidone gm 5 Hydroquinone gm 10 Potassium bromide gm 2 40% sodium hydroxide soln. to adj. pH to 10 5- methylbenzotriazole gm 0.125 Water to make liter 1 The processed sample contained a direct positive magenta dye image.

EXAMPLE 10 A sample of the film material was prepared and processed as described in Example v8 except that the following activator solution was used in place of the developer solution of Example 8:

Sodium thiosulfate gm 5 Benzotriazole gm 24 1-benzyl-2-picolinium bromide gm 13 Water to make liter 1 The pH of the solution was adj. to 12.5 with a 40% sodium hydroxide solution The processed sample contained a direct positive magenta dye image of a quality equal to that obtained according to the processes described in Examples 8 and 9.

15 EXAMPLE 11 A photographic silver-dye-bleach material was prepared by coating on a cellulose acetate film base, in sequence, the following layers:

Layer 1- Mg./ft. Gelatin 750 Layer 2- Yellow dye developer 42.5 Dispersed by means of N,N'-diethyl lauramide- 42.5 In gelatin 50.0

YELLOW DYE DEVELOPER l CH2GHzN=NC'2ICC ONHC4H9 O=C /N l H CaHs 1-pheny1-3-(N-butylcarbamyl) -4-{p-[B-(hydroquinonyl)- ethyl] -phenylazo} --pyrazolone Layer 3--Photographic silver bromoiodide emulsion coated to give a dry coverage of 55 -1ng./ft. of silver and 41 mg./ft. of gelatin Layer 4--Gelatin of a dry coverage of 32 mg./ft.

Three separate samples of the above material were processed, respectively, according to the procedures described in Examples 8, 9, and 10. In each instance, the reproduction obtained showed an excellent direct positive yellow dye image.

EXAMPLE 12 A photographic silver-dye-bleach material was prepared by coating on a cellulose acetate film base, in sequence, the following layers:

5 -hydroxy-1,4-bis 8- (hydroquinonyl) ethylamino1- anthraquinone Layer 2Red-sensitized silver halide emulsion coated to give a dry coverage of 210 rug/ft. of silver and 117 mg./ft. of gelatin Layer 3-Gelatin of a dry coverage of 586 mg./ft.

Three separate samples of the above material were processed respectively according to the procedures described in Examples; 8, .9 and 10. In each instance,'the obtained reproductions showed an excellent direct positive cyan dye image.

EXAMPLE 13 A silver-dye-bleach element was prepared by dispersing the magenta dye developer by means of diethyl lauramide and triethyl phosphate, in a green sensitized silver halide emulsion and coating the material on a white pigmented cellulose ester film support to give a dry coverage of 16 mg./ft. of silver, 300 mg./ft. of gelatin, and 50 mg/ft? of the dye developer:

2-{p- [fi-(hydroquinonyl)ethyl]phenylazo}-4-(,B- hydroxyethoxy)-l-naphthol After processing as described in Example 10, the element showed a direct positive magenta dye image.

EXAMPLE 14 Example 13 was repeated with a red-sensitized silver halide emulsion except that the dye developer used was the cyan dye developer.

S-hydroxy-lA-bis [fi-(hydroquinonyl)-a-(methyl)- ethylamino] anthraquin-one An excellent direct positive cyan image was obtained.

EXAMPLE 15 7 Example 13 was repeated with an essentially bluesensitive silver halide emulsion, except that the dye developer used was the yellow dye developer. 1-{4-[B-(hydroquinonyl)ethyl]phenyl} 3-[N-(3-hydroxypropyl)car bamyl] -4-(2-trifluoromethylphenylazo -5-pyrazolone N C ONHCHzCHzCHzOH A good, positive yellow image Was obtained.

EXAMPLE 16 Example 15 was repeated by using l-{4-[fi-(hydroquinonyl)ethyl]phenyl} 3 [N-(3-hydroxypropyl)carbamyl] -4- (3-trifluoromethylphenylazo -5-pyrazolone:

as the dye developer. A good yellow dye image was obtained.

EXAMPLE 17 Example 15 was repeated to obtain a yellow image by using 1 {4-['y-(hydroquinonyl)pr0pyl]phenyl} 3 (N- 1 7 hexylcarbamyl) 4-[3-(hydroquinonyl) phenylazo1-5-pyrazolone N: C ONHOQHB The following dye developers were used to prepare and process silver-dye-bleach elements as described in Example 12, each of which yielded a direct positive yellow dye image. 1-{4- [3- (hydroquinonyl ethyl] phenyl}-3-carbethoxy-4- 2,4-dimethylphenylazo -pyrazolone:

N=N 00002115 CH3 o1 I 1 CHzCH2 1-{4-[5-(hydroquinonyl)ethy1] phenyl}-3-[N-('y-hydroxypropyl carbamyl] -4*mesitylazo-5-pyrazolone:

1 phenyl 3 (N-amylcarbamyl) 4 {4-[B-(2,5-dihydroxy-4-methylphenyl ethyl] phenylazo}-5-pyrazolon'e:

C aHa 18 carbamyl) 4 (5,8-dihydroxy-2-naphthylazo)-5-pyrazo lone:

EXAMPLE 18 A photographic silver-dye-bleach material is prepared by coating on a cellulose acetate film base, in sequence the following layers:

Layer 1- M-g./ft. Cyan dye developer 128 Dispersed by means of N,N-diethyl lauramide 256 In gelatin 4-methyl-l-phenyl-3-pyrazolidone 10 Layer 2-- Red-sensitized silver halide emulsion coated to give a dry coverage of 210 mg/ft. of silver and 117 mg./ft. of gelatin.

Layer 3 Silver bromoiodide emulsion coated to give a dry coverage of 55 mg./ft. of silver and 41 mg./ft. of gelatin.

CYAN DYE DEVELOPER 5 hydroxy 1,4 bisDQ-(hydroquinonyl) a (methyl) ethylamino1anthraquinone NH-(FH-CHr- MAGENTA DYE DEVELOPER 2[p-(fl-hydroquihonylethyl)phenylazo] 4 ethoxy 1- naphthol:

H (511 El OH I CH2CHr N= I O Ql/ 1 9 YELLOW DYE DEVELOPER 1 {4-[,B-(hydroquinonyl)ethyl]phenyl} 3 [N-(3-hydroxypropyl)carbamyl] 4 (Z-trifiuoromethylphenylazo) -5 -pyrazolone The coating, after exposure and processing as described in Example 11, is found to show a multicolor direct positive dye reproduction of the photographed subject.

The dye developers of this invention may be utilized in the photo-sensitive element, for example in, on or behind the silver halide emulsion. In a preferred embodiment, the coatings or layers of the dye developer is placed behind the silver halide emulsion, which has the advantage of minimizing any light-filtering action by the colored dye developer.

Generally, when our photographic elements are processed to yield direct positive images according to the silverdye-bleach method, the pH of the black-and-white activator is adjusted to be below approximately 13 to prevent undesirable diffusion. Auxiliary developing agents of the type mentioned above may also be used in addition to dye-developers.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. The process of preparing photographic dye images in an exposed photographic element having light sensitive silver halide dispersed in a hydrophilic colloid layer coated on a support, said layer having in association therewith a non-diffusible bleachable dye and a developing agent, which comprises:

(a) contacting said element with an alkaline solution to develop the silver halide in the areas of exposure to metallic silver; and,

(b) bleaching said dye in the area of said metallic silver.

2. The process of preparing photographic dye images in an exposed photographic element having light sensitive silver halide dispersed in a hydrophilic colloid layer coated on a support, said layer having in association therewith a non-difiusible dye-developer, which comprises:

(a) contacting said element with an alkaline solution to develop the silver halide in the areas of exposure to metallic silver; and,

(b) bleaching said dye in the area of said metallic silver.

3. The process of preparing photographic dye images in an exposed photographic element having light sensitive silver halide dispersed in a hydrophilic colloid layer coated on a support, said layer having in association therewith a non-difiusible' bleachable dye and a developing agent free from any dye moiety which comprises:

(a) contacting said element with an alkaline solution 20 to develop the silver halide in the areas of exposure to metallic silver; and,

(b) bleaching said dye in the area of said metallic silver.

4. The process of preparing, photographic dye images in an exposed photographic element having coated thereon at least three separate overlying hydrophilic colloid layers containing silver halide, the silver halide in said layers being sensitized, respectively, to red, green and blue radiation and having in association therewith, re-

spectively, non-diffusible bleachable cyan, magenta and yellow dyes, each of said layers having in association therewith a developing agent, which comprises:

(a) contacting said element with an alkaline solution to develop the silver halide in the areas of exposure to metallic silver; and

(b)'bleaching said dye in the area of said metallic silver.

5. The process of preparing photographic dye images in an exposed photographic element having coated thereon at least three separate overlying hydrophilic 'colloid layers containing silver halide, the silver halide in said layers being sensitized, respectively, to red, green and blue radiation and having in association therewith, respectively, non-difiusible bleachable cyan, magenta and yellow dye-developers, which comprises:

(a) contacting said element with an alkaline solution to develop the silver halide in the areas of exposure to metallic silver While maintaining the pH of said element below that at which the dye-developer will diffuse in the hydrophilic colloid, and

(b) bleaching said dye in the area of said metallic silver.

6. The process of claim 4 wherein said developing agent is free from any dye moiety.

7. The method of producing a negative silver image in an exposed photographic element comprising a support having coated thereon a light-sensitive silver halide emulsion having a pH lower than about 7.0, said emulsion having in association therewith a bleachable dye and an alkali activatable developing agent, which comprises raising the pH of the emulsion to over about 9.0 but below the pH at which said bleachable dye diffuses from said emulsion.

8. The method of producing a negative silver image in an exposed photographic element suitable for providing multicolor images comprising a support having coated thereon separate overlying light-sensitive silver halide emulsion layers which are sensitized, respectively, to red, green and blue radiation and which have in association therewith, respectively, non-difiusible bleachable cyan, magenta and yellow dyes, said layers having a pH lower than about 7.0, and at least two separate, non-light-sensitive hydrophilic colloid layers containing a developing agent, said layers being arranged so that each of said lightsensitive layers is contiguous to at least one of said hydrophilic colloid layers, which comprises raising the pH of said emulsion layers to about 10.5.

9. The method of claim 8 wherein the developing agent is a combination of a dihydroxybenzene and a l-phenyl- 3-pyrazolidone.

10. The method of claim 7 wherein the bleachable dye and the developing agent are one compound, which is incorporated in the emulsion, having the formula:

on NHC-CHz-NH OH CHaO 11. A photographic element comprising a support having coated thereon a silver halide emulsion layer, said layer having in association therewith a developing agent free from any dye moiety and a non-diffusible bleachable dye.

12. A photographic element comprising a support having coated thereon a silver halide emulsion layer, said layer having in association therewith a non-difiusible bleachable dye, a dye-bleach catalyst and a developing agent free from any dye moiety.

13. A photographic element suitable for providing multicolor images comprising a support having coated thereon separate overlying light-sensitive silver halide emulsion layers, each of said layers having in association therewith a developing agent free from any dye moiety and a non-diifusible bleachable dye.

14. A photographic element suitable for providing multi-color images comprising a support having coated thereon separate overlying light-sensitive silver halide emulsion layers which are sensitized, respectively, to red, green and blue radiation and which have in association therewith, respectively, non-diitusible bleachable cyan, magenta and yellow dyes, and at least two separate, nonlight-sensitive hydrophilic colloid layers containing a developing agent free from any dye moiety, said layers being arranged so that each of said light-sensitive layers is contiguous to at least one of said hydrophilic colloid layers.

15. A photographic element suitable for providing multi-color images comprising a support having coated thereon separate overlying light-sensitive silver halide emulsion layers which are sensitized, respectively, to red, green and blue radiation and which have in association therewith, respectively, non-ditfusible bleachable cyan, magenta and yellow dyes, said light-sensitive layers having incorporated therein a dye-bleach catalyst, and at least two separate, non-light-sensitive hydrophilic colloid layers containing a developing agent free from any dye moiety, said layers being arranged so that each of said light-sensitive layers is contiguous to at least one of said hydrophilic colloid layers.

16. A photographic element suitable for providing multicolor images comprising a support having coated thereon three separate light-sensitive silver halide emulsion layers sensitized, respectively, to red, green and blue radiation, said layers containing, respectively, non-ditfusible bleachable cyan, magenta and yellow dyes, each of said layers containing an efiective concentration of a quinoxaline dye-bleach catalyst, said element also containing two separate hydrophilic colloid layers, the layers of said element being arranged so that each light-sensitive layer is contiguous to at least one of said hydrophilic colloid layers, each of said hydrophilic colloid layers having incorporated therein an effective concentration of norbornane hydroquinone and 1-phenyl-3-pyrazolidone developing agents to provide a negative silver image in at least one of said light-sensitive layers upon exposure and activation at a pH of about 10.5 with an alkaline solution.

17. A photographic element suitable for providing multicolor images comprising a support having coated thereon three separate light-sensitive silver halide emulsion layers sensitized, respectively, to red, green and blue radiation, said layers containing, respectively, non-diifnsible bleachable cyan, magenta and yellow dyes, each of said layers containing an eflective concentration of a dye bleach catalyst, said element also containing two separate hydrophilic colloid layers, the layers of said element being arranged so that each light-sensitive layer is contiguous to at least one of said hydrophilic colloid layers, each of said hydrophilic colloid layers having incorporated therein an effective concentration of a hydroquinone and a 3-pyrazolidone developing agent to provide a negative silver image in at least one of said light-sensitive layers upon exposure and activation at a pH of about 10.5 with an alkaline solution.

18. A photographic element suitable for providing multicolor images comprising a support having coated thereon three separate light-sensitive silver halide emulsion layers sensitized, respectively, to red, green and blue radiation, saidlayers containing, respectively, non-diffusible bleachable cyan, magenta and yellow dyes, each of said layers containing an effective concentration of a quinoxaline dye bleach catalyst, said element also containing two separate hydrophilic colloid layers, the layers of said element being arranged so that each light-sensitive layer is contiguous to at least one of said hydrophilic colloicl layers, each of said hydrophilic colloid layers having incorporated therein an effective concentration of a hydroquinone and a 3-pyrazolidone developing agent to provide a negative silver image in at least one of said light-sensitive layers upon exposure and activation at a pH of about 10.5 with an alkaline solution.

19. The method of claim 7 wherein the bleachable dye and the developing agent are one compound, which is incorporated in the emulsion, having the formula:

n d era-on,

20. The method of claim 7 wherein the bleachable dye and the developing agent are one compound, which is incorporated in the emulsion, having the formula:

21. The method of claim 7 wherein the bleachable dye and the developing agent are one compound, which is incorporated in the emulsion, having the formula:

(Bail References Cited NORMAN G. TORCHIN, Primary Examiner A. T. SURO-PICO, Assistant Examiner US. Cl. X.R. 9673 

